Oh, electric supercar, why do you tease us so? Mercedes is latest to throw up a prototype of what it expects future rubber burners to look like, and its SLS E-Cell doesn't disappoint. Based on its petrol-guzzling SLS AMG model, this beast produces 526 horsepower and 649 pound-feet of torque, thanks to four motors (one for each wheel) allied to a battery array that can provide an industry-leading 480kW of juice. How fast does that get you to the magical 60mph marker? Try four seconds. There's a handsome 10-inch infotainment panel in the cen
